It is known to manufacture floor structures with a flooring of, for instance parquet and situated on two layers of parallel joists, wherein the joists of one layer extend perpendicular to the joists of the second layer, and wherein the two layers of joists abut one another directly and are situated on chocking means arranged at regular intervals. The joists abutting the chocking means directly are provided with a sawn vertical cut extending preferably into half thickness. Such a flooring does not, however, provide flexibility over a surface, i.e., so-called surface flexibility, which is sufficient for sports floor. The latter is especially due to the fact that the floor structure does not have sufficient flexibility on the sites were the joists of the two layers are intersecting. The cuts in the lower layer of joists damp the transmission of vertical oscillations in the flooring during use.